Microscopes of the generic type, in particular microscopes in which two objectives that are directed toward one another and have a common focus in the image plane are provided, have been known in practical use for some time. Reference is made in this context, merely by way of example, to EP 0 491 289 B1. This document discloses a double confocal scanning microscope having the generic features. Specifically, what is described therein is a scanning microscope in which a non-polarizing beam splitter apparatus is provided to split the illuminating light into coherent portions. The beam splitter apparatus serves to illuminate the objectives directed toward one another, and to combine mutually coherent light beams from the objectives that are directed toward one another. High resolution can be obtained with the optical components implemented therein.
The microscope known from EP 0 491 289 B1 is a so-called “high-end” microscope, in which an interferometric beam path is implemented. A microscope of this kind is of extremely complex design and is therefore—even in its basic version—expensive compared to conventional microscopes. In addition, these “high-end” microscopes are special constructions that require a great deal of room on optical benches and accordingly are also very susceptible to external influences. Above all, however, the “high-end” microscopy provided for therein requires a special microscope, with no possibility of using conventional microscopes with their capabilities.